One-dimensional superdiffusive heat propagation induced by optical phonon-phonon interactions
One-dimensional superdiffusive heat propagation induced by optical phonon-phonon interactions
复制标题
光学声子-声子相互作用引起的一维超扩散热传播
DOI：
10.1103/physreve.98.012130
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发表时间：
2018
影响因子：
2.4
通讯作者：
Zhang Yong
中科院分区：
文献类型：
--
作者：
Xiong Daxing;Zhang Yong
一维反常热传播通常由Lévy walk超扩散扩散函数表征，由于声学声子的有限速度，该函数具有位于前沿的两个侧峰。在声学声子消失的情况下，例如，由于声子-晶格相互作用使得系统的动量不守恒，侧峰将消失，并且将观察到正常的高斯扩散热传播行为。在这里，我们表明，存在另一种新类型的超扩散，非高斯热传播，但没有侧峰在一个典型的非声学，动量非守恒系统。这意味着该系统中的热输运不服从傅立叶定律，与现有的理论预测形成鲜明对比。其基本机制与光学声子-声子相互作用的效应有关。这些发现可能为进一步探索低维热输运开辟了一条新的途径。
One-dimensional anomalous heat propagation is usually characterized by a Lévy walk superdiffusive spreading function with two side peaks located on the fronts due to the finite velocity of acoustic phonons. In the case when the acoustic phonons vanish, e.g., due to the phonon-lattice interactions such that the system's momentum is not conserved, the side peaks will disappear and a normal Gaussian diffusive heat-propagating behavior will be observed. Here we show that there exists another new type of superdiffusive, non-Gaussian heat propagation but without side peaks in a typical nonacoustic, momentum-nonconserving system. It implies that thermal transport in this system disobeys the Fourier law, in clear contrast with the existing theoretical predictions. The underlying mechanism is related to an effect of optical phonon-phonon interactions. These findings may open a new avenue for further exploring thermal transport in low dimensions.